Over the years, various proposals have been made for electrically powered vehicles. To date, for a number of reasons, electric vehicle systems have yet to become commercial for urban and highway applications.
There have been proposals to employ zinc/air batteries for urban vehicle propulsion. An example is the following publication:
Improved slurry zinc/air systems as batteries for urban vehicle propulsion, by P.C. Foller, Journal of Applied Electrochemistry 16 (1986), 527-543.
Metal/air battery structures are described in the following publications:
U.S. Pat. No. 4,842,963, entitled Zinc Electrode and Rechargeable Zinc-Air Battery;
U.S. Pat. No. 4,147,839, entitled Electrochemical Cell with Stirred Slurry;
U.S. Pat. No. 4,908,281, entitled Metal/air Battery with Recirculating Electrolyte;
U.S.Pat. No. 4,925,744, entitled Primary Aluminum-Air Battery;
U.S. Pat. No. 3,716,413, entitled Rechargeable Electrochemical Power Supply;
U.S. Pat. No. 4,925,744, entitled Primary Aluminum-Air Battery;
Electrical energy storage systems are described in the following publications:
U.S. Pat. No. 4,843,251 entitled Energy Storage and Supply Recirculating Electrolyte;
Energy on Call by John A. Casazza et al, IEEE Spectrum June, 1976, pp 44-47.
U.S. Pat. No. 4,275,310, entitled Peak Power Generation;
U.S. Pat. No. 4,124,805, entitled Pollution-Free Power Generating and Peak Power Load Shaving System;
U.S. Pat. No. 4,797,566, entitled Energy Storing Apparatus.
U.S. Pat. No. 3,847,671, entitled Hydraulically-Refuelable Metal-Gas Depolarized Battery System, describes metal-gas battery system constructed so that both solid and liquid contents can be drained from the battery after discharge. There are provided a negative grid and a gas depolarized electrode which together define a compartment that can be refilled with a slurry of electrolyte and an active metal powder, thereby recharging the battery in a relatively short time. There is also provided means for flushing out the battery with an electrolyte solution prior to refilling with a fresh batch of slurry.
The teachings of the foregoing publications are hereby incorporated herein by reference.
As described, for example, in U.S. Pat. No. 3,847,671, the replacement of a discharged metal-based slurry in a metal-air power storage system conventionally requires pumped removal of discharged slurry from the system, and the pumping of fresh slurry into the system.
In providing batteries that are powerful enough to power relatively heavy objects such as vehicles, it is an aim to maximize the current density of the battery. In achieving this, however, metal-air battery systems are becoming of increasingly more lightweight construction and they are less able, therefore, to withstand the pressures that may be caused by the pumping of slurry, both into and out of the battery.
The following additional references describe various energy storage systems: U.S. Pat. Nos. 3,414,437; 3,647,542; 3,979,222; 3,849,202; 4,136,232; 4,166,885 and 4,517,248.
U.S. Pat. No. 4,294,891, entitled Intermittently Refuelable Implantable Bio-Oxidant Fuel Cell, describes the use of a soluble liquid fuel supported between cathode and anode assemblies each of which includes a current collector formed of expanded gold mesh.